No major trends in ease of accuracy between the two similar to how the 88 doesn't shoot well for many people?
No. 80 X's and 88 M's have both been very hit and miss in 223s and 22 creeds for me. 80 Xs probably even more so than the 88 Ms, but I've shot much more of them.
73 and 80 Ms have faired better accuracy wise and have been less picky on speed, barrel twist, etc. Also, for whatever reason, while lower volume from me than 80 Xs and 88 M's, the terminal "issues" I've seen in 108 and 88 M's hasn't happened as often with the 80 Ms. Likely just happenstance and low enough volume.
80 X's have been very consistent killers for me, nearly indistinguishable from 77 TMKs in nearly all cases. It's just been difficult to get them to shoot under 1.75-2.25 MOA lot to lot, barrel to barrel, etc.
I think we are putting carts before the horses here in general. ELDMs are great killing bullets and it takes actually opening up enough animals (and paying attention) and/or shooting reduced loads into good gel recipes to see meaningful trends. Most the time, you won't even see anything other than excellent wounds with Ms.
Again, I've been a vocal proponent on this site favoring overall wound reliability/performance of SSTs and ELDXs over ELDMs in general since I joined this site. This doesn't mean that ELDM's perform "poorly" it's mostly splitting hairs and is "evidence" that nearly all will never see.
TLDR: Shoot whatever your gun shoots the best. Stop chasing max speed with non hunting safe loads and watch your groups tighten up. Velocity trumps BC out to most realistic hunting ranges with most shooters. 77 TMKs continue to be the least picky, most consistent lot to lot, and create the most reliable and repeatable killing wounds within the .224 world in what I've seen. I don't really see any reason to deviate from those little brickhouse bastards and if you say "because shit BC" stop it
